I forgot to add that I usually use the Costco's 3" tabs for maintenance. I have to use tabs because I'm out of town ALL THE TIME, and my wife doesn't want to mess with chemicals. I see that they have a little bit o'copper, but I've still got most of the bucket left from last year. Any big problems with me using it up this season?

We didn't have any green hair last year. :-)

DuPont Trichloro-s-triazinetrione 93.5%
Copper sulphate pentahydrate 1.5%